EP 0056712 B1 19840919 - INFORMATION READ APPARATUS WITH TRACKING CONTROL SYSTEM
Title (en)
INFORMATION READ APPARATUS WITH TRACKING CONTROL SYSTEM
Publication
Application
Priority
JP 527181 A 19810116
Abstract (en)
[origin: US4488276A] An information read apparatus with tracking control system comprises a first closed loop and a second closed loop. The first closed loop performs high speed tracking control and feedback compensation for damping the tracking control system, with the aid of a means for detecting the tracking error without excess frequency dependency. The second closed loop performs precise tracking control with the aid of tracking error detection by wobbling the reading position on the information carrier in a direction traverse to the information track being read. The second closed loop is dominant only in the low frequency region. Since the second closed loop is negligible in comparison with the first closed loop near the cross-over frequency of the tracking control system, phase lag of the second closed loop is allowable about said cross-over frequency. Therefore, the wobbling frequency can be selected so low that the same actuator that controls the global reading position can be used for wobbling. In this way, the tracking control system performs both of high precision control and high speed control.
IPC 1-7
IPC 8 full level
G02B 7/28 (2006.01); G11B 7/09 (2006.01); G11B 21/10 (2006.01)
CPC (source: EP US)
G11B 7/0904 (2013.01 - EP US); G11B 21/10 (2013.01 - EP US)
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
US 4488276 A 19841211; DE 3260743 D1 19841025; EP 0056712 A2 19820728; EP 0056712 A3 19820811; EP 0056712 B1 19840919; JP S57120238 A 19820727; JP S6223372 B2 19870522
DOCDB simple family (application)
US 33950982 A 19820115; DE 3260743 T 19820115; EP 82300203 A 19820115; JP 527181 A 19810116